1. Field of the Disclosure
This disclosure relates to a method of fabricating a liquid crystal display (LCD) device.
2. Description of the Related Art
Liquid crystal display (LCD) devices have gradually attracted wide attention, as a replacement that can overcome drawbacks of cathode ray tubes (CRTs), because of its advantages such as compact size, light weight, and low power consumption. Recently, LCD devices are employed in nearly all information processing apparatuses needing display devices.
The LCD device uses modulation of light by liquid crystal cells, that is, by applying a voltage to a specific molecule arrangement of liquid crystal, the molecule arrangement is converted to other molecule arrangement so that a change of optical properties is converted to a visual change.
The LCD device is fabricated by a various processes including manufacturing upper and lower substrates of a panel, which is accompanied by a process of forming liquid cells that forms a pixel unit, forming and rubbing an orientation film for liquid crystal orientation, adhesively combining the upper and lower substrates, and injecting liquid crystal between the adhesively combined upper and lower substrates and sealing the upper and lower substrates.
In the lower substrate manufacturing process, a unit pixel region is defined by arranging a plurality of gate lines and data lines to cross each other. A thin film transistor (TFT) that is a switching element and a pixel electrode are formed in each pixel region. The TFT is turned on by a driving signal supplied through the gate line and performs a switching function to provide a graphic signal that is supplied through the data line, to a pixel electrode. The graphic signal provided to the pixel electrode generates an electric field to rotate liquid crystal and thus converts external or internal light to display an image.
In particular, as the LCD device becomes large and high resolution, technology to provide the pixel region with a high aperture ratio and a high transmittance has been developed. For the LCD device to have a high aperture ratio and a high transmittance, the width of each of the gate line, the data line, the pixel electrode, and a common electrode arranged within a predetermined pixel region is formed to be narrow.
However, it is difficult to reduce the width of a line or electrode that is patterned, to be not greater than 4 μm, due to the physical properties of an exposure equipment used in a method of fabricating an LCD device. That is, the width of a line or electrode that can be formed through the processes of forming a metal film on a substrate, coating a photoresist film, performing a mask process, and performing exposure, development, and etching processes, is greater than 4 μm.
The width of a line or electrode may not be further decreased due to the limit in the resolutions of a mask and an exposure equipment used in the LCD device fabrication process. Thus, it is difficult to form the width of a line or electrode formed on an array substrate of an LCD device, to be not greater than 4 μm, by using a currently used equipment.
Thus, an LCD device having higher aperture ratio and transmittance may not be fabricated unless the width of a line or electrode formed in a pixel region of the LCD device to be not greater than 4 μm.